Greg Stiemsma leaves Celtics, Keyon Dooling staying

Stiemsma, a backup center, is joining the Minnesota Timberwolves as a free agent while the Celtics decide to re-sign veteran guard Dooling.

Jim Fenton

The Celtics have lost one member of their 2011-12 team to free agency, but they have retained another.

Backup center Greg Stiemsma, who was a rookie at the age of 26 this past season, has agreed to terms with the Minnesota Timberwolves.

Reserve point guard Keyon Dooling, meanwhile, will return to the Celtics with a one-year contract worth the veteran’s minimum of $1.35 million.

The Celtics were unable to match the offer sheet, estimated at nearly $3 million, that Stiemsma signed with the Timberwolves last week.

Stiemsma, who was a restricted free agent, had received a qualifying offer of just over $1 million from Boston, but the Celtics rescinded that this week and allowed him to leave. He joins Ray Allen, who departed for the Miami Heat, in exiting the Celtics.

“I’m very grateful to the Celtics and the city of Boston, but I’m very excited to be the newest member of the Minnesota Timberwolves,’’ said Stiemsma on Twitter.

Stiemsma was an unexpected addition to the Celtics’ training camp roster following the lockout last December, earned a roster spot, then became a rotation player.

He made the NBA after doing very little in four seasons at Wisconsin and bouncing around with teams in Turkey, South Korea and the NBDL in three years after college.

In 55 games with the Celtics, Stiemsma averaged 2.9 points and blocked a team-best 85 shots (21 more than Kevin Garnett, who was second).

Stiemsma, who struggled with foot injuries, backed up Garnett when he was shifted to center.

The Celtics have signed free agents Chris Wilcox and Jason Collins to be reserves in the frontcourt.

Dooling played 46 games with the Celtics last season, averaging 4 points as a backup to Rajon Rondo. The 32-year-old Dooling was a positive influence among his teammates.

Playing time for Dooling is expected to be limited with guards Jason Terry and Courtney Lee signing free-agent deals.

Another free agent, Mickael Pietrus, is also expected to leave the Celtics in the near future. The team can only offer Pietrus just under $2 million, and he will probably get a better deal elsewhere.